The use of luminescent materials for e.g. safety applications is known in the art. U.S. Pat. No. 4,401,050, for instance, describes a phosphorescent escape route indicator having at least one protruding indicia formed within or attached to a sheet of material. The protruding indicia have incorporated therewith a phosphorescent substance capable of emitting a glow in the absence of light. An adhesive formed as part of the sheet is utilized to apply the indicator to the surface of walls or stairways thereby aiding in delineating escape routes or access routes to emergency equipment during time of emergency.